We have fabricated a novel near-infrared light source for optical coherence tomography (OCT) using a glass phosphor and a light emitting diode (LED) as the excitation source. We used 1.glass as the phosphor to obtain wideband light emission around 1000 nm. We observed a full-width at half-maximum (FWHM) as wide as 98 nm with an output power as high as 1 mW. The interference signal showed a coherence length of 4.6 m. This value indicates that the depth resolution of the OCT is twice as high as that of conventional LEDs and super luminescent diodes (SLDs). #

We have investigated the spectroscopic properties of Bi 2 O 3 -B 2 O 3 glasses doped with Nd 3þ and Yb 3þ separately, and doubly doped with the same ions, in order to search for appropriate phosphors for an optical coherence tomography (OCT) light source. The effects of Yb 3þ and Nd 3þ co-doping and varying Yb 3þ concentration on the spectrum shape were studied to obtain an optimum line shape for OCT. We successfully obtained a Gaussian-like shape spectrum from 5.0Yb 2 O 3 -1.0Nd 2 O 3 -46.0Bi 2 O 3 -46.0B 2 O 3 (in nominal molar composition) with a full-width-at-half-maximum (FWHM) of 101 nm in the wavelength region around 1000 nm. This FWHM corresponds to a depth resolution of 4.5 mm, which is about twice that of conventional light emitting diodes (LEDs) and super luminescent diodes (SLDs). The Gaussian-like line shape is very important to suppress ghost images in OCT. These results indicate that a Yb 3þ , Nd 3þ co-doped Bi 2 O 3 -B 2 O 3 glass phosphor can indeed be applied as a new type of OCT light source.

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We have investigated spectroscopic properties of Bi2O3‐GeO2 glass co‐doped with Yb3+ and Nd3+ to find appropriate phosphors for an optical coherence tomography (OCT) light source. We have successfully obtained a Gaussian‐like shaped spectrum from 6.0 Yb2O3–5.0 Nd2O3–44.0 Bi2O3–44.0 GeO2–1.0 Sb2O3 (in nominal molar composition) with a full width at half maximum (FWHM) of 91 nm in the wavelength region near 1000 nm. We achieved the luminescence efficiency of 1.4% using a green LED. The interference signal was studied by using a Michelson interferometer. As a result, the coherent length of 5.7 μm was achieved. This value indicates that the depth resolution of the OCT with this light source is twice compared with that of conventional SLDs. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)